Two methods question

[unfair]

So my first method was CO that I throughly thought through, bought the materials, and have completely planned out. I'm waiting for my CO meter to come in the mail so I can test. But then researched and acquired SN. I don't have the nausea medicine yet but I have an appointment soon and should be able to get it. Can I do both to insure death?

 

[BPD Barbie]

Usually overlapping methods isn't advised. One of those is enough to do the job, 2 is just setting yourself up for more things to go wrong.

 

[unfair]

Considering I live alone and can acquire everything I need for CO and possibly everything for SN, which would be preferred?